Nanoscale Model Catalyst Paves Way Toward Atomic-Level
Understanding

NEW YORK, NY — In an attempt to understand why ruthenium
sulfide (RuS2) is so good at removing sulfur
impurities from fuels, scientists at the U.S. Department of
Energy’s Brookhaven National Laboratory have succeeded in making
a model of this catalyst — nanoparticles supported on an inert
surface — which can be studied under laboratory conditions. “If
we can understand why this catalyst is so active, we might be
able to make it even better, or use what we learn to design
other highly efficient catalysts,” said Tanhong Cai, one of the
scientists who made the model.

Removing sulfur from fossil fuels such as oil and coal is
mandated because the resulting fuels burn more cleanly and
efficiently. One common way of achieving this is to add hydrogen
in the presence of a catalyst to release hydrogen sulfide (H2S).
Recently, RuS2 was found to be 100 times more active
than the catalyst most commonly used for this
“hydrodesulfurization” reaction. But studying the catalyst in
action is nearly impossible because the reaction takes place at
high temperatures and under extreme pressure.

The Brookhaven team has therefore created a model of the
catalyst via a chemical reaction that deposits nanosized
particles of RuS2 on a nonreactive gold surface. The
small size of the particles maximizes the surface area available
for the catalytic reaction to take place, and makes it ideal for
analysis by classic surface chemistry techniques, such as
scanning tunneling microscopy and x-ray photoemission
spectroscopy. The entire model is being studied under
well-defined ultrahigh vacuum conditions.

Cai will present a talk on the preparation and
characterization of this model catalyst during the
“Size-Selected Clusters on Surfaces, Divison of Physical
Chemistry” session on Monday, September 8, 2003, at 4:30 p.m. in
the Javits Convention Center, Room 1E10. This work was funded by
the Division of Chemical Sciences, Office of Basic Energy
Sciences at DOE’s Office of Science.

The
U.S. Department of Energy's Brookhaven National Laboratory conducts
research in the physical, biomedical, and environmental sciences, as
well as in energy technologies. Brookhaven also builds and operates
major facilities available to university, industrial, and government
scientists. The Laboratory is managed by Brookhaven Science
Associates, a limited liability company founded by Stony Brook
University and Battelle, a nonprofit applied science and technology
organization.